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Caption

Neck bones. Frontal 3D CT (computed tomography) scan of normal neck bones (cervical vertebrae, C1- C7). These make up the top part of the spine. The bone at top is the atlas (C1), which has a complicated joint with the skull, allowing several types of movement of the head. Below that is the axis (C2). Descending downwards from the axis are five other cervical vertebrae (C3-C7), separated by intervertebral discs (blue). The remaining vertebrae of the upper and lower back are not shown. The bony protrusions either side of the spine are the vertebral processes, where neck and back muscles are attached. The spine protects the spinal cord, and flexes to allow movement of the torso and neck.